2 * Copyright (C) 2011-2012 Red Hat UK.
4 * This file is released under the GPL.
7 #include "dm-thin-metadata.h"
8 #include "dm-bio-prison.h"
11 #include <linux/device-mapper.h>
12 #include <linux/dm-io.h>
13 #include <linux/dm-kcopyd.h>
14 #include <linux/list.h>
15 #include <linux/init.h>
16 #include <linux/module.h>
17 #include <linux/slab.h>
19 #define DM_MSG_PREFIX "thin"
24 #define ENDIO_HOOK_POOL_SIZE 1024
25 #define MAPPING_POOL_SIZE 1024
26 #define PRISON_CELLS 1024
27 #define COMMIT_PERIOD HZ
29 DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(snapshot_copy_throttle,
30 "A percentage of time allocated for copy on write");
33 * The block size of the device holding pool data must be
34 * between 64KB and 1GB.
36 #define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (64 * 1024 >> SECTOR_SHIFT)
37 #define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT)
40 * Device id is restricted to 24 bits.
42 #define MAX_DEV_ID ((1 << 24) - 1)
45 * How do we handle breaking sharing of data blocks?
46 * =================================================
48 * We use a standard copy-on-write btree to store the mappings for the
49 * devices (note I'm talking about copy-on-write of the metadata here, not
50 * the data). When you take an internal snapshot you clone the root node
51 * of the origin btree. After this there is no concept of an origin or a
52 * snapshot. They are just two device trees that happen to point to the
55 * When we get a write in we decide if it's to a shared data block using
56 * some timestamp magic. If it is, we have to break sharing.
58 * Let's say we write to a shared block in what was the origin. The
61 * i) plug io further to this physical block. (see bio_prison code).
63 * ii) quiesce any read io to that shared data block. Obviously
64 * including all devices that share this block. (see dm_deferred_set code)
66 * iii) copy the data block to a newly allocate block. This step can be
67 * missed out if the io covers the block. (schedule_copy).
69 * iv) insert the new mapping into the origin's btree
70 * (process_prepared_mapping). This act of inserting breaks some
71 * sharing of btree nodes between the two devices. Breaking sharing only
72 * effects the btree of that specific device. Btrees for the other
73 * devices that share the block never change. The btree for the origin
74 * device as it was after the last commit is untouched, ie. we're using
75 * persistent data structures in the functional programming sense.
77 * v) unplug io to this physical block, including the io that triggered
78 * the breaking of sharing.
80 * Steps (ii) and (iii) occur in parallel.
82 * The metadata _doesn't_ need to be committed before the io continues. We
83 * get away with this because the io is always written to a _new_ block.
84 * If there's a crash, then:
86 * - The origin mapping will point to the old origin block (the shared
87 * one). This will contain the data as it was before the io that triggered
88 * the breaking of sharing came in.
90 * - The snap mapping still points to the old block. As it would after
93 * The downside of this scheme is the timestamp magic isn't perfect, and
94 * will continue to think that data block in the snapshot device is shared
95 * even after the write to the origin has broken sharing. I suspect data
96 * blocks will typically be shared by many different devices, so we're
97 * breaking sharing n + 1 times, rather than n, where n is the number of
98 * devices that reference this data block. At the moment I think the
99 * benefits far, far outweigh the disadvantages.
102 /*----------------------------------------------------------------*/
107 static void build_data_key(struct dm_thin_device *td,
108 dm_block_t b, struct dm_cell_key *key)
111 key->dev = dm_thin_dev_id(td);
115 static void build_virtual_key(struct dm_thin_device *td, dm_block_t b,
116 struct dm_cell_key *key)
119 key->dev = dm_thin_dev_id(td);
123 /*----------------------------------------------------------------*/
126 * A pool device ties together a metadata device and a data device. It
127 * also provides the interface for creating and destroying internal
130 struct dm_thin_new_mapping;
133 * The pool runs in 3 modes. Ordered in degraded order for comparisons.
136 PM_WRITE, /* metadata may be changed */
137 PM_READ_ONLY, /* metadata may not be changed */
138 PM_FAIL, /* all I/O fails */
141 struct pool_features {
144 bool zero_new_blocks:1;
145 bool discard_enabled:1;
146 bool discard_passdown:1;
150 typedef void (*process_bio_fn)(struct thin_c *tc, struct bio *bio);
151 typedef void (*process_mapping_fn)(struct dm_thin_new_mapping *m);
154 struct list_head list;
155 struct dm_target *ti; /* Only set if a pool target is bound */
157 struct mapped_device *pool_md;
158 struct block_device *md_dev;
159 struct dm_pool_metadata *pmd;
161 dm_block_t low_water_blocks;
162 uint32_t sectors_per_block;
163 int sectors_per_block_shift;
165 struct pool_features pf;
166 unsigned low_water_triggered:1; /* A dm event has been sent */
167 unsigned no_free_space:1; /* A -ENOSPC warning has been issued */
169 struct dm_bio_prison *prison;
170 struct dm_kcopyd_client *copier;
172 struct workqueue_struct *wq;
173 struct work_struct worker;
174 struct delayed_work waker;
176 unsigned long last_commit_jiffies;
180 struct bio_list deferred_bios;
181 struct bio_list deferred_flush_bios;
182 struct list_head prepared_mappings;
183 struct list_head prepared_discards;
185 struct bio_list retry_on_resume_list;
187 struct dm_deferred_set *shared_read_ds;
188 struct dm_deferred_set *all_io_ds;
190 struct dm_thin_new_mapping *next_mapping;
191 mempool_t *mapping_pool;
193 process_bio_fn process_bio;
194 process_bio_fn process_discard;
196 process_mapping_fn process_prepared_mapping;
197 process_mapping_fn process_prepared_discard;
200 static enum pool_mode get_pool_mode(struct pool *pool);
201 static void set_pool_mode(struct pool *pool, enum pool_mode mode);
204 * Target context for a pool.
207 struct dm_target *ti;
209 struct dm_dev *data_dev;
210 struct dm_dev *metadata_dev;
211 struct dm_target_callbacks callbacks;
213 dm_block_t low_water_blocks;
214 struct pool_features requested_pf; /* Features requested during table load */
215 struct pool_features adjusted_pf; /* Features used after adjusting for constituent devices */
219 * Target context for a thin.
222 struct dm_dev *pool_dev;
223 struct dm_dev *origin_dev;
227 struct dm_thin_device *td;
230 /*----------------------------------------------------------------*/
233 * wake_worker() is used when new work is queued and when pool_resume is
234 * ready to continue deferred IO processing.
236 static void wake_worker(struct pool *pool)
238 queue_work(pool->wq, &pool->worker);
241 /*----------------------------------------------------------------*/
243 static int bio_detain(struct pool *pool, struct dm_cell_key *key, struct bio *bio,
244 struct dm_bio_prison_cell **cell_result)
247 struct dm_bio_prison_cell *cell_prealloc;
250 * Allocate a cell from the prison's mempool.
251 * This might block but it can't fail.
253 cell_prealloc = dm_bio_prison_alloc_cell(pool->prison, GFP_NOIO);
255 r = dm_bio_detain(pool->prison, key, bio, cell_prealloc, cell_result);
258 * We reused an old cell; we can get rid of
261 dm_bio_prison_free_cell(pool->prison, cell_prealloc);
266 static void cell_release(struct pool *pool,
267 struct dm_bio_prison_cell *cell,
268 struct bio_list *bios)
270 dm_cell_release(pool->prison, cell, bios);
271 dm_bio_prison_free_cell(pool->prison, cell);
274 static void cell_release_no_holder(struct pool *pool,
275 struct dm_bio_prison_cell *cell,
276 struct bio_list *bios)
278 dm_cell_release_no_holder(pool->prison, cell, bios);
279 dm_bio_prison_free_cell(pool->prison, cell);
282 static void cell_defer_no_holder_no_free(struct thin_c *tc,
283 struct dm_bio_prison_cell *cell)
285 struct pool *pool = tc->pool;
288 spin_lock_irqsave(&pool->lock, flags);
289 dm_cell_release_no_holder(pool->prison, cell, &pool->deferred_bios);
290 spin_unlock_irqrestore(&pool->lock, flags);
295 static void cell_error(struct pool *pool,
296 struct dm_bio_prison_cell *cell)
298 dm_cell_error(pool->prison, cell);
299 dm_bio_prison_free_cell(pool->prison, cell);
302 /*----------------------------------------------------------------*/
305 * A global list of pools that uses a struct mapped_device as a key.
307 static struct dm_thin_pool_table {
309 struct list_head pools;
310 } dm_thin_pool_table;
312 static void pool_table_init(void)
314 mutex_init(&dm_thin_pool_table.mutex);
315 INIT_LIST_HEAD(&dm_thin_pool_table.pools);
318 static void __pool_table_insert(struct pool *pool)
320 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
321 list_add(&pool->list, &dm_thin_pool_table.pools);
324 static void __pool_table_remove(struct pool *pool)
326 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
327 list_del(&pool->list);
330 static struct pool *__pool_table_lookup(struct mapped_device *md)
332 struct pool *pool = NULL, *tmp;
334 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
336 list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
337 if (tmp->pool_md == md) {
346 static struct pool *__pool_table_lookup_metadata_dev(struct block_device *md_dev)
348 struct pool *pool = NULL, *tmp;
350 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
352 list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
353 if (tmp->md_dev == md_dev) {
362 /*----------------------------------------------------------------*/
364 struct dm_thin_endio_hook {
366 struct dm_deferred_entry *shared_read_entry;
367 struct dm_deferred_entry *all_io_entry;
368 struct dm_thin_new_mapping *overwrite_mapping;
371 static void __requeue_bio_list(struct thin_c *tc, struct bio_list *master)
374 struct bio_list bios;
376 bio_list_init(&bios);
377 bio_list_merge(&bios, master);
378 bio_list_init(master);
380 while ((bio = bio_list_pop(&bios))) {
381 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
384 bio_endio(bio, DM_ENDIO_REQUEUE);
386 bio_list_add(master, bio);
390 static void requeue_io(struct thin_c *tc)
392 struct pool *pool = tc->pool;
395 spin_lock_irqsave(&pool->lock, flags);
396 __requeue_bio_list(tc, &pool->deferred_bios);
397 __requeue_bio_list(tc, &pool->retry_on_resume_list);
398 spin_unlock_irqrestore(&pool->lock, flags);
402 * This section of code contains the logic for processing a thin device's IO.
403 * Much of the code depends on pool object resources (lists, workqueues, etc)
404 * but most is exclusively called from the thin target rather than the thin-pool
408 static bool block_size_is_power_of_two(struct pool *pool)
410 return pool->sectors_per_block_shift >= 0;
413 static dm_block_t get_bio_block(struct thin_c *tc, struct bio *bio)
415 struct pool *pool = tc->pool;
416 sector_t block_nr = bio->bi_iter.bi_sector;
418 if (block_size_is_power_of_two(pool))
419 block_nr >>= pool->sectors_per_block_shift;
421 (void) sector_div(block_nr, pool->sectors_per_block);
426 static void remap(struct thin_c *tc, struct bio *bio, dm_block_t block)
428 struct pool *pool = tc->pool;
429 sector_t bi_sector = bio->bi_iter.bi_sector;
431 bio->bi_bdev = tc->pool_dev->bdev;
432 if (block_size_is_power_of_two(pool))
433 bio->bi_iter.bi_sector =
434 (block << pool->sectors_per_block_shift) |
435 (bi_sector & (pool->sectors_per_block - 1));
437 bio->bi_iter.bi_sector = (block * pool->sectors_per_block) +
438 sector_div(bi_sector, pool->sectors_per_block);
441 static void remap_to_origin(struct thin_c *tc, struct bio *bio)
443 bio->bi_bdev = tc->origin_dev->bdev;
446 static int bio_triggers_commit(struct thin_c *tc, struct bio *bio)
448 return (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) &&
449 dm_thin_changed_this_transaction(tc->td);
452 static void inc_all_io_entry(struct pool *pool, struct bio *bio)
454 struct dm_thin_endio_hook *h;
456 if (bio->bi_rw & REQ_DISCARD)
459 h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
460 h->all_io_entry = dm_deferred_entry_inc(pool->all_io_ds);
463 static void issue(struct thin_c *tc, struct bio *bio)
465 struct pool *pool = tc->pool;
468 if (!bio_triggers_commit(tc, bio)) {
469 generic_make_request(bio);
474 * Complete bio with an error if earlier I/O caused changes to
475 * the metadata that can't be committed e.g, due to I/O errors
476 * on the metadata device.
478 if (dm_thin_aborted_changes(tc->td)) {
484 * Batch together any bios that trigger commits and then issue a
485 * single commit for them in process_deferred_bios().
487 spin_lock_irqsave(&pool->lock, flags);
488 bio_list_add(&pool->deferred_flush_bios, bio);
489 spin_unlock_irqrestore(&pool->lock, flags);
492 static void remap_to_origin_and_issue(struct thin_c *tc, struct bio *bio)
494 remap_to_origin(tc, bio);
498 static void remap_and_issue(struct thin_c *tc, struct bio *bio,
501 remap(tc, bio, block);
505 /*----------------------------------------------------------------*/
508 * Bio endio functions.
510 struct dm_thin_new_mapping {
511 struct list_head list;
515 unsigned pass_discard:1;
518 dm_block_t virt_block;
519 dm_block_t data_block;
520 struct dm_bio_prison_cell *cell, *cell2;
524 * If the bio covers the whole area of a block then we can avoid
525 * zeroing or copying. Instead this bio is hooked. The bio will
526 * still be in the cell, so care has to be taken to avoid issuing
530 bio_end_io_t *saved_bi_end_io;
533 static void __maybe_add_mapping(struct dm_thin_new_mapping *m)
535 struct pool *pool = m->tc->pool;
537 if (m->quiesced && m->prepared) {
538 list_add(&m->list, &pool->prepared_mappings);
543 static void copy_complete(int read_err, unsigned long write_err, void *context)
546 struct dm_thin_new_mapping *m = context;
547 struct pool *pool = m->tc->pool;
549 m->err = read_err || write_err ? -EIO : 0;
551 spin_lock_irqsave(&pool->lock, flags);
553 __maybe_add_mapping(m);
554 spin_unlock_irqrestore(&pool->lock, flags);
557 static void overwrite_endio(struct bio *bio, int err)
560 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
561 struct dm_thin_new_mapping *m = h->overwrite_mapping;
562 struct pool *pool = m->tc->pool;
566 spin_lock_irqsave(&pool->lock, flags);
568 __maybe_add_mapping(m);
569 spin_unlock_irqrestore(&pool->lock, flags);
572 /*----------------------------------------------------------------*/
579 * Prepared mapping jobs.
583 * This sends the bios in the cell back to the deferred_bios list.
585 static void cell_defer(struct thin_c *tc, struct dm_bio_prison_cell *cell)
587 struct pool *pool = tc->pool;
590 spin_lock_irqsave(&pool->lock, flags);
591 cell_release(pool, cell, &pool->deferred_bios);
592 spin_unlock_irqrestore(&tc->pool->lock, flags);
598 * Same as cell_defer above, except it omits the original holder of the cell.
600 static void cell_defer_no_holder(struct thin_c *tc, struct dm_bio_prison_cell *cell)
602 struct pool *pool = tc->pool;
605 spin_lock_irqsave(&pool->lock, flags);
606 cell_release_no_holder(pool, cell, &pool->deferred_bios);
607 spin_unlock_irqrestore(&pool->lock, flags);
612 static void process_prepared_mapping_fail(struct dm_thin_new_mapping *m)
615 m->bio->bi_end_io = m->saved_bi_end_io;
616 atomic_inc(&m->bio->bi_remaining);
618 cell_error(m->tc->pool, m->cell);
620 mempool_free(m, m->tc->pool->mapping_pool);
623 static void process_prepared_mapping(struct dm_thin_new_mapping *m)
625 struct thin_c *tc = m->tc;
626 struct pool *pool = tc->pool;
632 bio->bi_end_io = m->saved_bi_end_io;
633 atomic_inc(&bio->bi_remaining);
637 cell_error(pool, m->cell);
642 * Commit the prepared block into the mapping btree.
643 * Any I/O for this block arriving after this point will get
644 * remapped to it directly.
646 r = dm_thin_insert_block(tc->td, m->virt_block, m->data_block);
648 DMERR_LIMIT("%s: dm_thin_insert_block() failed: error = %d",
649 dm_device_name(pool->pool_md), r);
650 set_pool_mode(pool, PM_READ_ONLY);
651 cell_error(pool, m->cell);
656 * Release any bios held while the block was being provisioned.
657 * If we are processing a write bio that completely covers the block,
658 * we already processed it so can ignore it now when processing
659 * the bios in the cell.
662 cell_defer_no_holder(tc, m->cell);
665 cell_defer(tc, m->cell);
669 mempool_free(m, pool->mapping_pool);
672 static void process_prepared_discard_fail(struct dm_thin_new_mapping *m)
674 struct thin_c *tc = m->tc;
676 bio_io_error(m->bio);
677 cell_defer_no_holder(tc, m->cell);
678 cell_defer_no_holder(tc, m->cell2);
679 mempool_free(m, tc->pool->mapping_pool);
682 static void process_prepared_discard_passdown(struct dm_thin_new_mapping *m)
684 struct thin_c *tc = m->tc;
686 inc_all_io_entry(tc->pool, m->bio);
687 cell_defer_no_holder(tc, m->cell);
688 cell_defer_no_holder(tc, m->cell2);
691 remap_and_issue(tc, m->bio, m->data_block);
693 bio_endio(m->bio, 0);
695 mempool_free(m, tc->pool->mapping_pool);
698 static void process_prepared_discard(struct dm_thin_new_mapping *m)
701 struct thin_c *tc = m->tc;
703 r = dm_thin_remove_block(tc->td, m->virt_block);
705 DMERR_LIMIT("dm_thin_remove_block() failed");
707 process_prepared_discard_passdown(m);
710 static void process_prepared(struct pool *pool, struct list_head *head,
711 process_mapping_fn *fn)
714 struct list_head maps;
715 struct dm_thin_new_mapping *m, *tmp;
717 INIT_LIST_HEAD(&maps);
718 spin_lock_irqsave(&pool->lock, flags);
719 list_splice_init(head, &maps);
720 spin_unlock_irqrestore(&pool->lock, flags);
722 list_for_each_entry_safe(m, tmp, &maps, list)
729 static int io_overlaps_block(struct pool *pool, struct bio *bio)
731 return bio->bi_iter.bi_size ==
732 (pool->sectors_per_block << SECTOR_SHIFT);
735 static int io_overwrites_block(struct pool *pool, struct bio *bio)
737 return (bio_data_dir(bio) == WRITE) &&
738 io_overlaps_block(pool, bio);
741 static void save_and_set_endio(struct bio *bio, bio_end_io_t **save,
744 *save = bio->bi_end_io;
748 static int ensure_next_mapping(struct pool *pool)
750 if (pool->next_mapping)
753 pool->next_mapping = mempool_alloc(pool->mapping_pool, GFP_ATOMIC);
755 return pool->next_mapping ? 0 : -ENOMEM;
758 static struct dm_thin_new_mapping *get_next_mapping(struct pool *pool)
760 struct dm_thin_new_mapping *r = pool->next_mapping;
762 BUG_ON(!pool->next_mapping);
764 pool->next_mapping = NULL;
769 static void schedule_copy(struct thin_c *tc, dm_block_t virt_block,
770 struct dm_dev *origin, dm_block_t data_origin,
771 dm_block_t data_dest,
772 struct dm_bio_prison_cell *cell, struct bio *bio)
775 struct pool *pool = tc->pool;
776 struct dm_thin_new_mapping *m = get_next_mapping(pool);
778 INIT_LIST_HEAD(&m->list);
782 m->virt_block = virt_block;
783 m->data_block = data_dest;
788 if (!dm_deferred_set_add_work(pool->shared_read_ds, &m->list))
792 * IO to pool_dev remaps to the pool target's data_dev.
794 * If the whole block of data is being overwritten, we can issue the
795 * bio immediately. Otherwise we use kcopyd to clone the data first.
797 if (io_overwrites_block(pool, bio)) {
798 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
800 h->overwrite_mapping = m;
802 save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio);
803 inc_all_io_entry(pool, bio);
804 remap_and_issue(tc, bio, data_dest);
806 struct dm_io_region from, to;
808 from.bdev = origin->bdev;
809 from.sector = data_origin * pool->sectors_per_block;
810 from.count = pool->sectors_per_block;
812 to.bdev = tc->pool_dev->bdev;
813 to.sector = data_dest * pool->sectors_per_block;
814 to.count = pool->sectors_per_block;
816 r = dm_kcopyd_copy(pool->copier, &from, 1, &to,
817 0, copy_complete, m);
819 mempool_free(m, pool->mapping_pool);
820 DMERR_LIMIT("dm_kcopyd_copy() failed");
821 cell_error(pool, cell);
826 static void schedule_internal_copy(struct thin_c *tc, dm_block_t virt_block,
827 dm_block_t data_origin, dm_block_t data_dest,
828 struct dm_bio_prison_cell *cell, struct bio *bio)
830 schedule_copy(tc, virt_block, tc->pool_dev,
831 data_origin, data_dest, cell, bio);
834 static void schedule_external_copy(struct thin_c *tc, dm_block_t virt_block,
835 dm_block_t data_dest,
836 struct dm_bio_prison_cell *cell, struct bio *bio)
838 schedule_copy(tc, virt_block, tc->origin_dev,
839 virt_block, data_dest, cell, bio);
842 static void schedule_zero(struct thin_c *tc, dm_block_t virt_block,
843 dm_block_t data_block, struct dm_bio_prison_cell *cell,
846 struct pool *pool = tc->pool;
847 struct dm_thin_new_mapping *m = get_next_mapping(pool);
849 INIT_LIST_HEAD(&m->list);
853 m->virt_block = virt_block;
854 m->data_block = data_block;
860 * If the whole block of data is being overwritten or we are not
861 * zeroing pre-existing data, we can issue the bio immediately.
862 * Otherwise we use kcopyd to zero the data first.
864 if (!pool->pf.zero_new_blocks)
865 process_prepared_mapping(m);
867 else if (io_overwrites_block(pool, bio)) {
868 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
870 h->overwrite_mapping = m;
872 save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio);
873 inc_all_io_entry(pool, bio);
874 remap_and_issue(tc, bio, data_block);
877 struct dm_io_region to;
879 to.bdev = tc->pool_dev->bdev;
880 to.sector = data_block * pool->sectors_per_block;
881 to.count = pool->sectors_per_block;
883 r = dm_kcopyd_zero(pool->copier, 1, &to, 0, copy_complete, m);
885 mempool_free(m, pool->mapping_pool);
886 DMERR_LIMIT("dm_kcopyd_zero() failed");
887 cell_error(pool, cell);
893 * A non-zero return indicates read_only or fail_io mode.
894 * Many callers don't care about the return value.
896 static int commit(struct pool *pool)
900 if (get_pool_mode(pool) != PM_WRITE)
903 r = dm_pool_commit_metadata(pool->pmd);
905 DMERR_LIMIT("%s: dm_pool_commit_metadata failed: error = %d",
906 dm_device_name(pool->pool_md), r);
907 set_pool_mode(pool, PM_READ_ONLY);
913 static int alloc_data_block(struct thin_c *tc, dm_block_t *result)
916 dm_block_t free_blocks;
918 struct pool *pool = tc->pool;
921 * Once no_free_space is set we must not allow allocation to succeed.
922 * Otherwise it is difficult to explain, debug, test and support.
924 if (pool->no_free_space)
927 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
931 if (free_blocks <= pool->low_water_blocks && !pool->low_water_triggered) {
932 DMWARN("%s: reached low water mark for data device: sending event.",
933 dm_device_name(pool->pool_md));
934 spin_lock_irqsave(&pool->lock, flags);
935 pool->low_water_triggered = 1;
936 spin_unlock_irqrestore(&pool->lock, flags);
937 dm_table_event(pool->ti->table);
942 * Try to commit to see if that will free up some
949 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
954 * If we still have no space we set a flag to avoid
955 * doing all this checking and return -ENOSPC. This
956 * flag serves as a latch that disallows allocations from
957 * this pool until the admin takes action (e.g. resize or
961 DMWARN("%s: no free data space available.",
962 dm_device_name(pool->pool_md));
963 spin_lock_irqsave(&pool->lock, flags);
964 pool->no_free_space = 1;
965 spin_unlock_irqrestore(&pool->lock, flags);
970 r = dm_pool_alloc_data_block(pool->pmd, result);
973 !dm_pool_get_free_metadata_block_count(pool->pmd, &free_blocks) &&
975 DMWARN("%s: no free metadata space available.",
976 dm_device_name(pool->pool_md));
977 set_pool_mode(pool, PM_READ_ONLY);
986 * If we have run out of space, queue bios until the device is
987 * resumed, presumably after having been reloaded with more space.
989 static void retry_on_resume(struct bio *bio)
991 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
992 struct thin_c *tc = h->tc;
993 struct pool *pool = tc->pool;
996 spin_lock_irqsave(&pool->lock, flags);
997 bio_list_add(&pool->retry_on_resume_list, bio);
998 spin_unlock_irqrestore(&pool->lock, flags);
1001 static void no_space(struct pool *pool, struct dm_bio_prison_cell *cell)
1004 struct bio_list bios;
1006 bio_list_init(&bios);
1007 cell_release(pool, cell, &bios);
1009 while ((bio = bio_list_pop(&bios)))
1010 retry_on_resume(bio);
1013 static void process_discard(struct thin_c *tc, struct bio *bio)
1016 unsigned long flags;
1017 struct pool *pool = tc->pool;
1018 struct dm_bio_prison_cell *cell, *cell2;
1019 struct dm_cell_key key, key2;
1020 dm_block_t block = get_bio_block(tc, bio);
1021 struct dm_thin_lookup_result lookup_result;
1022 struct dm_thin_new_mapping *m;
1024 build_virtual_key(tc->td, block, &key);
1025 if (bio_detain(tc->pool, &key, bio, &cell))
1028 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1032 * Check nobody is fiddling with this pool block. This can
1033 * happen if someone's in the process of breaking sharing
1036 build_data_key(tc->td, lookup_result.block, &key2);
1037 if (bio_detain(tc->pool, &key2, bio, &cell2)) {
1038 cell_defer_no_holder(tc, cell);
1042 if (io_overlaps_block(pool, bio)) {
1044 * IO may still be going to the destination block. We must
1045 * quiesce before we can do the removal.
1047 m = get_next_mapping(pool);
1049 m->pass_discard = (!lookup_result.shared) && pool->pf.discard_passdown;
1050 m->virt_block = block;
1051 m->data_block = lookup_result.block;
1057 if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list)) {
1058 spin_lock_irqsave(&pool->lock, flags);
1059 list_add(&m->list, &pool->prepared_discards);
1060 spin_unlock_irqrestore(&pool->lock, flags);
1064 inc_all_io_entry(pool, bio);
1065 cell_defer_no_holder(tc, cell);
1066 cell_defer_no_holder(tc, cell2);
1069 * The DM core makes sure that the discard doesn't span
1070 * a block boundary. So we submit the discard of a
1071 * partial block appropriately.
1073 if ((!lookup_result.shared) && pool->pf.discard_passdown)
1074 remap_and_issue(tc, bio, lookup_result.block);
1082 * It isn't provisioned, just forget it.
1084 cell_defer_no_holder(tc, cell);
1089 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1091 cell_defer_no_holder(tc, cell);
1097 static void break_sharing(struct thin_c *tc, struct bio *bio, dm_block_t block,
1098 struct dm_cell_key *key,
1099 struct dm_thin_lookup_result *lookup_result,
1100 struct dm_bio_prison_cell *cell)
1103 dm_block_t data_block;
1104 struct pool *pool = tc->pool;
1106 r = alloc_data_block(tc, &data_block);
1109 schedule_internal_copy(tc, block, lookup_result->block,
1110 data_block, cell, bio);
1114 no_space(pool, cell);
1118 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1120 set_pool_mode(pool, PM_READ_ONLY);
1121 cell_error(pool, cell);
1126 static void process_shared_bio(struct thin_c *tc, struct bio *bio,
1128 struct dm_thin_lookup_result *lookup_result)
1130 struct dm_bio_prison_cell *cell;
1131 struct pool *pool = tc->pool;
1132 struct dm_cell_key key;
1135 * If cell is already occupied, then sharing is already in the process
1136 * of being broken so we have nothing further to do here.
1138 build_data_key(tc->td, lookup_result->block, &key);
1139 if (bio_detain(pool, &key, bio, &cell))
1142 if (bio_data_dir(bio) == WRITE && bio->bi_iter.bi_size)
1143 break_sharing(tc, bio, block, &key, lookup_result, cell);
1145 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1147 h->shared_read_entry = dm_deferred_entry_inc(pool->shared_read_ds);
1148 inc_all_io_entry(pool, bio);
1149 cell_defer_no_holder(tc, cell);
1151 remap_and_issue(tc, bio, lookup_result->block);
1155 static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block,
1156 struct dm_bio_prison_cell *cell)
1159 dm_block_t data_block;
1160 struct pool *pool = tc->pool;
1163 * Remap empty bios (flushes) immediately, without provisioning.
1165 if (!bio->bi_iter.bi_size) {
1166 inc_all_io_entry(pool, bio);
1167 cell_defer_no_holder(tc, cell);
1169 remap_and_issue(tc, bio, 0);
1174 * Fill read bios with zeroes and complete them immediately.
1176 if (bio_data_dir(bio) == READ) {
1178 cell_defer_no_holder(tc, cell);
1183 r = alloc_data_block(tc, &data_block);
1187 schedule_external_copy(tc, block, data_block, cell, bio);
1189 schedule_zero(tc, block, data_block, cell, bio);
1193 no_space(pool, cell);
1197 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1199 set_pool_mode(pool, PM_READ_ONLY);
1200 cell_error(pool, cell);
1205 static void process_bio(struct thin_c *tc, struct bio *bio)
1208 struct pool *pool = tc->pool;
1209 dm_block_t block = get_bio_block(tc, bio);
1210 struct dm_bio_prison_cell *cell;
1211 struct dm_cell_key key;
1212 struct dm_thin_lookup_result lookup_result;
1215 * If cell is already occupied, then the block is already
1216 * being provisioned so we have nothing further to do here.
1218 build_virtual_key(tc->td, block, &key);
1219 if (bio_detain(pool, &key, bio, &cell))
1222 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1225 if (lookup_result.shared) {
1226 process_shared_bio(tc, bio, block, &lookup_result);
1227 cell_defer_no_holder(tc, cell); /* FIXME: pass this cell into process_shared? */
1229 inc_all_io_entry(pool, bio);
1230 cell_defer_no_holder(tc, cell);
1232 remap_and_issue(tc, bio, lookup_result.block);
1237 if (bio_data_dir(bio) == READ && tc->origin_dev) {
1238 inc_all_io_entry(pool, bio);
1239 cell_defer_no_holder(tc, cell);
1241 remap_to_origin_and_issue(tc, bio);
1243 provision_block(tc, bio, block, cell);
1247 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1249 cell_defer_no_holder(tc, cell);
1255 static void process_bio_read_only(struct thin_c *tc, struct bio *bio)
1258 int rw = bio_data_dir(bio);
1259 dm_block_t block = get_bio_block(tc, bio);
1260 struct dm_thin_lookup_result lookup_result;
1262 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1265 if (lookup_result.shared && (rw == WRITE) && bio->bi_iter.bi_size)
1268 inc_all_io_entry(tc->pool, bio);
1269 remap_and_issue(tc, bio, lookup_result.block);
1279 if (tc->origin_dev) {
1280 inc_all_io_entry(tc->pool, bio);
1281 remap_to_origin_and_issue(tc, bio);
1290 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1297 static void process_bio_fail(struct thin_c *tc, struct bio *bio)
1303 * FIXME: should we also commit due to size of transaction, measured in
1306 static int need_commit_due_to_time(struct pool *pool)
1308 return jiffies < pool->last_commit_jiffies ||
1309 jiffies > pool->last_commit_jiffies + COMMIT_PERIOD;
1312 static void process_deferred_bios(struct pool *pool)
1314 unsigned long flags;
1316 struct bio_list bios;
1318 bio_list_init(&bios);
1320 spin_lock_irqsave(&pool->lock, flags);
1321 bio_list_merge(&bios, &pool->deferred_bios);
1322 bio_list_init(&pool->deferred_bios);
1323 spin_unlock_irqrestore(&pool->lock, flags);
1325 while ((bio = bio_list_pop(&bios))) {
1326 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1327 struct thin_c *tc = h->tc;
1330 * If we've got no free new_mapping structs, and processing
1331 * this bio might require one, we pause until there are some
1332 * prepared mappings to process.
1334 if (ensure_next_mapping(pool)) {
1335 spin_lock_irqsave(&pool->lock, flags);
1336 bio_list_merge(&pool->deferred_bios, &bios);
1337 spin_unlock_irqrestore(&pool->lock, flags);
1342 if (bio->bi_rw & REQ_DISCARD)
1343 pool->process_discard(tc, bio);
1345 pool->process_bio(tc, bio);
1349 * If there are any deferred flush bios, we must commit
1350 * the metadata before issuing them.
1352 bio_list_init(&bios);
1353 spin_lock_irqsave(&pool->lock, flags);
1354 bio_list_merge(&bios, &pool->deferred_flush_bios);
1355 bio_list_init(&pool->deferred_flush_bios);
1356 spin_unlock_irqrestore(&pool->lock, flags);
1358 if (bio_list_empty(&bios) && !need_commit_due_to_time(pool))
1362 while ((bio = bio_list_pop(&bios)))
1366 pool->last_commit_jiffies = jiffies;
1368 while ((bio = bio_list_pop(&bios)))
1369 generic_make_request(bio);
1372 static void do_worker(struct work_struct *ws)
1374 struct pool *pool = container_of(ws, struct pool, worker);
1376 process_prepared(pool, &pool->prepared_mappings, &pool->process_prepared_mapping);
1377 process_prepared(pool, &pool->prepared_discards, &pool->process_prepared_discard);
1378 process_deferred_bios(pool);
1382 * We want to commit periodically so that not too much
1383 * unwritten data builds up.
1385 static void do_waker(struct work_struct *ws)
1387 struct pool *pool = container_of(to_delayed_work(ws), struct pool, waker);
1389 queue_delayed_work(pool->wq, &pool->waker, COMMIT_PERIOD);
1392 /*----------------------------------------------------------------*/
1394 static enum pool_mode get_pool_mode(struct pool *pool)
1396 return pool->pf.mode;
1399 static void set_pool_mode(struct pool *pool, enum pool_mode mode)
1403 pool->pf.mode = mode;
1407 DMERR("%s: switching pool to failure mode",
1408 dm_device_name(pool->pool_md));
1409 dm_pool_metadata_read_only(pool->pmd);
1410 pool->process_bio = process_bio_fail;
1411 pool->process_discard = process_bio_fail;
1412 pool->process_prepared_mapping = process_prepared_mapping_fail;
1413 pool->process_prepared_discard = process_prepared_discard_fail;
1417 DMERR("%s: switching pool to read-only mode",
1418 dm_device_name(pool->pool_md));
1419 r = dm_pool_abort_metadata(pool->pmd);
1421 DMERR("%s: aborting transaction failed",
1422 dm_device_name(pool->pool_md));
1423 set_pool_mode(pool, PM_FAIL);
1425 dm_pool_metadata_read_only(pool->pmd);
1426 pool->process_bio = process_bio_read_only;
1427 pool->process_discard = process_discard;
1428 pool->process_prepared_mapping = process_prepared_mapping_fail;
1429 pool->process_prepared_discard = process_prepared_discard_passdown;
1434 dm_pool_metadata_read_write(pool->pmd);
1435 pool->process_bio = process_bio;
1436 pool->process_discard = process_discard;
1437 pool->process_prepared_mapping = process_prepared_mapping;
1438 pool->process_prepared_discard = process_prepared_discard;
1443 /*----------------------------------------------------------------*/
1446 * Mapping functions.
1450 * Called only while mapping a thin bio to hand it over to the workqueue.
1452 static void thin_defer_bio(struct thin_c *tc, struct bio *bio)
1454 unsigned long flags;
1455 struct pool *pool = tc->pool;
1457 spin_lock_irqsave(&pool->lock, flags);
1458 bio_list_add(&pool->deferred_bios, bio);
1459 spin_unlock_irqrestore(&pool->lock, flags);
1464 static void thin_hook_bio(struct thin_c *tc, struct bio *bio)
1466 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1469 h->shared_read_entry = NULL;
1470 h->all_io_entry = NULL;
1471 h->overwrite_mapping = NULL;
1475 * Non-blocking function called from the thin target's map function.
1477 static int thin_bio_map(struct dm_target *ti, struct bio *bio)
1480 struct thin_c *tc = ti->private;
1481 dm_block_t block = get_bio_block(tc, bio);
1482 struct dm_thin_device *td = tc->td;
1483 struct dm_thin_lookup_result result;
1484 struct dm_bio_prison_cell cell1, cell2;
1485 struct dm_bio_prison_cell *cell_result;
1486 struct dm_cell_key key;
1488 thin_hook_bio(tc, bio);
1490 if (get_pool_mode(tc->pool) == PM_FAIL) {
1492 return DM_MAPIO_SUBMITTED;
1495 if (bio->bi_rw & (REQ_DISCARD | REQ_FLUSH | REQ_FUA)) {
1496 thin_defer_bio(tc, bio);
1497 return DM_MAPIO_SUBMITTED;
1500 r = dm_thin_find_block(td, block, 0, &result);
1503 * Note that we defer readahead too.
1507 if (unlikely(result.shared)) {
1509 * We have a race condition here between the
1510 * result.shared value returned by the lookup and
1511 * snapshot creation, which may cause new
1514 * To avoid this always quiesce the origin before
1515 * taking the snap. You want to do this anyway to
1516 * ensure a consistent application view
1519 * More distant ancestors are irrelevant. The
1520 * shared flag will be set in their case.
1522 thin_defer_bio(tc, bio);
1523 return DM_MAPIO_SUBMITTED;
1526 build_virtual_key(tc->td, block, &key);
1527 if (dm_bio_detain(tc->pool->prison, &key, bio, &cell1, &cell_result))
1528 return DM_MAPIO_SUBMITTED;
1530 build_data_key(tc->td, result.block, &key);
1531 if (dm_bio_detain(tc->pool->prison, &key, bio, &cell2, &cell_result)) {
1532 cell_defer_no_holder_no_free(tc, &cell1);
1533 return DM_MAPIO_SUBMITTED;
1536 inc_all_io_entry(tc->pool, bio);
1537 cell_defer_no_holder_no_free(tc, &cell2);
1538 cell_defer_no_holder_no_free(tc, &cell1);
1540 remap(tc, bio, result.block);
1541 return DM_MAPIO_REMAPPED;
1544 if (get_pool_mode(tc->pool) == PM_READ_ONLY) {
1546 * This block isn't provisioned, and we have no way
1547 * of doing so. Just error it.
1550 return DM_MAPIO_SUBMITTED;
1556 * In future, the failed dm_thin_find_block above could
1557 * provide the hint to load the metadata into cache.
1559 thin_defer_bio(tc, bio);
1560 return DM_MAPIO_SUBMITTED;
1564 * Must always call bio_io_error on failure.
1565 * dm_thin_find_block can fail with -EINVAL if the
1566 * pool is switched to fail-io mode.
1569 return DM_MAPIO_SUBMITTED;
1573 static int pool_is_congested(struct dm_target_callbacks *cb, int bdi_bits)
1576 unsigned long flags;
1577 struct pool_c *pt = container_of(cb, struct pool_c, callbacks);
1579 spin_lock_irqsave(&pt->pool->lock, flags);
1580 r = !bio_list_empty(&pt->pool->retry_on_resume_list);
1581 spin_unlock_irqrestore(&pt->pool->lock, flags);
1584 struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
1585 r = bdi_congested(&q->backing_dev_info, bdi_bits);
1591 static void __requeue_bios(struct pool *pool)
1593 bio_list_merge(&pool->deferred_bios, &pool->retry_on_resume_list);
1594 bio_list_init(&pool->retry_on_resume_list);
1597 /*----------------------------------------------------------------
1598 * Binding of control targets to a pool object
1599 *--------------------------------------------------------------*/
1600 static bool data_dev_supports_discard(struct pool_c *pt)
1602 struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
1604 return q && blk_queue_discard(q);
1607 static bool is_factor(sector_t block_size, uint32_t n)
1609 return !sector_div(block_size, n);
1613 * If discard_passdown was enabled verify that the data device
1614 * supports discards. Disable discard_passdown if not.
1616 static void disable_passdown_if_not_supported(struct pool_c *pt)
1618 struct pool *pool = pt->pool;
1619 struct block_device *data_bdev = pt->data_dev->bdev;
1620 struct queue_limits *data_limits = &bdev_get_queue(data_bdev)->limits;
1621 sector_t block_size = pool->sectors_per_block << SECTOR_SHIFT;
1622 const char *reason = NULL;
1623 char buf[BDEVNAME_SIZE];
1625 if (!pt->adjusted_pf.discard_passdown)
1628 if (!data_dev_supports_discard(pt))
1629 reason = "discard unsupported";
1631 else if (data_limits->max_discard_sectors < pool->sectors_per_block)
1632 reason = "max discard sectors smaller than a block";
1634 else if (data_limits->discard_granularity > block_size)
1635 reason = "discard granularity larger than a block";
1637 else if (!is_factor(block_size, data_limits->discard_granularity))
1638 reason = "discard granularity not a factor of block size";
1641 DMWARN("Data device (%s) %s: Disabling discard passdown.", bdevname(data_bdev, buf), reason);
1642 pt->adjusted_pf.discard_passdown = false;
1646 static int bind_control_target(struct pool *pool, struct dm_target *ti)
1648 struct pool_c *pt = ti->private;
1651 * We want to make sure that a pool in PM_FAIL mode is never upgraded.
1653 enum pool_mode old_mode = pool->pf.mode;
1654 enum pool_mode new_mode = pt->adjusted_pf.mode;
1657 * If we were in PM_FAIL mode, rollback of metadata failed. We're
1658 * not going to recover without a thin_repair. So we never let the
1659 * pool move out of the old mode. On the other hand a PM_READ_ONLY
1660 * may have been due to a lack of metadata or data space, and may
1661 * now work (ie. if the underlying devices have been resized).
1663 if (old_mode == PM_FAIL)
1664 new_mode = old_mode;
1667 pool->low_water_blocks = pt->low_water_blocks;
1668 pool->pf = pt->adjusted_pf;
1670 set_pool_mode(pool, new_mode);
1675 static void unbind_control_target(struct pool *pool, struct dm_target *ti)
1681 /*----------------------------------------------------------------
1683 *--------------------------------------------------------------*/
1684 /* Initialize pool features. */
1685 static void pool_features_init(struct pool_features *pf)
1687 pf->mode = PM_WRITE;
1688 pf->zero_new_blocks = true;
1689 pf->discard_enabled = true;
1690 pf->discard_passdown = true;
1693 static void __pool_destroy(struct pool *pool)
1695 __pool_table_remove(pool);
1697 if (dm_pool_metadata_close(pool->pmd) < 0)
1698 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
1700 dm_bio_prison_destroy(pool->prison);
1701 dm_kcopyd_client_destroy(pool->copier);
1704 destroy_workqueue(pool->wq);
1706 if (pool->next_mapping)
1707 mempool_free(pool->next_mapping, pool->mapping_pool);
1708 mempool_destroy(pool->mapping_pool);
1709 dm_deferred_set_destroy(pool->shared_read_ds);
1710 dm_deferred_set_destroy(pool->all_io_ds);
1714 static struct kmem_cache *_new_mapping_cache;
1716 static struct pool *pool_create(struct mapped_device *pool_md,
1717 struct block_device *metadata_dev,
1718 unsigned long block_size,
1719 int read_only, char **error)
1724 struct dm_pool_metadata *pmd;
1725 bool format_device = read_only ? false : true;
1727 pmd = dm_pool_metadata_open(metadata_dev, block_size, format_device);
1729 *error = "Error creating metadata object";
1730 return (struct pool *)pmd;
1733 pool = kmalloc(sizeof(*pool), GFP_KERNEL);
1735 *error = "Error allocating memory for pool";
1736 err_p = ERR_PTR(-ENOMEM);
1741 pool->sectors_per_block = block_size;
1742 if (block_size & (block_size - 1))
1743 pool->sectors_per_block_shift = -1;
1745 pool->sectors_per_block_shift = __ffs(block_size);
1746 pool->low_water_blocks = 0;
1747 pool_features_init(&pool->pf);
1748 pool->prison = dm_bio_prison_create(PRISON_CELLS);
1749 if (!pool->prison) {
1750 *error = "Error creating pool's bio prison";
1751 err_p = ERR_PTR(-ENOMEM);
1755 pool->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle);
1756 if (IS_ERR(pool->copier)) {
1757 r = PTR_ERR(pool->copier);
1758 *error = "Error creating pool's kcopyd client";
1760 goto bad_kcopyd_client;
1764 * Create singlethreaded workqueue that will service all devices
1765 * that use this metadata.
1767 pool->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
1769 *error = "Error creating pool's workqueue";
1770 err_p = ERR_PTR(-ENOMEM);
1774 INIT_WORK(&pool->worker, do_worker);
1775 INIT_DELAYED_WORK(&pool->waker, do_waker);
1776 spin_lock_init(&pool->lock);
1777 bio_list_init(&pool->deferred_bios);
1778 bio_list_init(&pool->deferred_flush_bios);
1779 INIT_LIST_HEAD(&pool->prepared_mappings);
1780 INIT_LIST_HEAD(&pool->prepared_discards);
1781 pool->low_water_triggered = 0;
1782 pool->no_free_space = 0;
1783 bio_list_init(&pool->retry_on_resume_list);
1785 pool->shared_read_ds = dm_deferred_set_create();
1786 if (!pool->shared_read_ds) {
1787 *error = "Error creating pool's shared read deferred set";
1788 err_p = ERR_PTR(-ENOMEM);
1789 goto bad_shared_read_ds;
1792 pool->all_io_ds = dm_deferred_set_create();
1793 if (!pool->all_io_ds) {
1794 *error = "Error creating pool's all io deferred set";
1795 err_p = ERR_PTR(-ENOMEM);
1799 pool->next_mapping = NULL;
1800 pool->mapping_pool = mempool_create_slab_pool(MAPPING_POOL_SIZE,
1801 _new_mapping_cache);
1802 if (!pool->mapping_pool) {
1803 *error = "Error creating pool's mapping mempool";
1804 err_p = ERR_PTR(-ENOMEM);
1805 goto bad_mapping_pool;
1808 pool->ref_count = 1;
1809 pool->last_commit_jiffies = jiffies;
1810 pool->pool_md = pool_md;
1811 pool->md_dev = metadata_dev;
1812 __pool_table_insert(pool);
1817 dm_deferred_set_destroy(pool->all_io_ds);
1819 dm_deferred_set_destroy(pool->shared_read_ds);
1821 destroy_workqueue(pool->wq);
1823 dm_kcopyd_client_destroy(pool->copier);
1825 dm_bio_prison_destroy(pool->prison);
1829 if (dm_pool_metadata_close(pmd))
1830 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
1835 static void __pool_inc(struct pool *pool)
1837 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
1841 static void __pool_dec(struct pool *pool)
1843 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
1844 BUG_ON(!pool->ref_count);
1845 if (!--pool->ref_count)
1846 __pool_destroy(pool);
1849 static struct pool *__pool_find(struct mapped_device *pool_md,
1850 struct block_device *metadata_dev,
1851 unsigned long block_size, int read_only,
1852 char **error, int *created)
1854 struct pool *pool = __pool_table_lookup_metadata_dev(metadata_dev);
1857 if (pool->pool_md != pool_md) {
1858 *error = "metadata device already in use by a pool";
1859 return ERR_PTR(-EBUSY);
1864 pool = __pool_table_lookup(pool_md);
1866 if (pool->md_dev != metadata_dev) {
1867 *error = "different pool cannot replace a pool";
1868 return ERR_PTR(-EINVAL);
1873 pool = pool_create(pool_md, metadata_dev, block_size, read_only, error);
1881 /*----------------------------------------------------------------
1882 * Pool target methods
1883 *--------------------------------------------------------------*/
1884 static void pool_dtr(struct dm_target *ti)
1886 struct pool_c *pt = ti->private;
1888 mutex_lock(&dm_thin_pool_table.mutex);
1890 unbind_control_target(pt->pool, ti);
1891 __pool_dec(pt->pool);
1892 dm_put_device(ti, pt->metadata_dev);
1893 dm_put_device(ti, pt->data_dev);
1896 mutex_unlock(&dm_thin_pool_table.mutex);
1899 static int parse_pool_features(struct dm_arg_set *as, struct pool_features *pf,
1900 struct dm_target *ti)
1904 const char *arg_name;
1906 static struct dm_arg _args[] = {
1907 {0, 3, "Invalid number of pool feature arguments"},
1911 * No feature arguments supplied.
1916 r = dm_read_arg_group(_args, as, &argc, &ti->error);
1920 while (argc && !r) {
1921 arg_name = dm_shift_arg(as);
1924 if (!strcasecmp(arg_name, "skip_block_zeroing"))
1925 pf->zero_new_blocks = false;
1927 else if (!strcasecmp(arg_name, "ignore_discard"))
1928 pf->discard_enabled = false;
1930 else if (!strcasecmp(arg_name, "no_discard_passdown"))
1931 pf->discard_passdown = false;
1933 else if (!strcasecmp(arg_name, "read_only"))
1934 pf->mode = PM_READ_ONLY;
1937 ti->error = "Unrecognised pool feature requested";
1946 static void metadata_low_callback(void *context)
1948 struct pool *pool = context;
1950 DMWARN("%s: reached low water mark for metadata device: sending event.",
1951 dm_device_name(pool->pool_md));
1953 dm_table_event(pool->ti->table);
1956 static sector_t get_metadata_dev_size(struct block_device *bdev)
1958 sector_t metadata_dev_size = i_size_read(bdev->bd_inode) >> SECTOR_SHIFT;
1959 char buffer[BDEVNAME_SIZE];
1961 if (metadata_dev_size > THIN_METADATA_MAX_SECTORS_WARNING) {
1962 DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.",
1963 bdevname(bdev, buffer), THIN_METADATA_MAX_SECTORS);
1964 metadata_dev_size = THIN_METADATA_MAX_SECTORS_WARNING;
1967 return metadata_dev_size;
1970 static dm_block_t get_metadata_dev_size_in_blocks(struct block_device *bdev)
1972 sector_t metadata_dev_size = get_metadata_dev_size(bdev);
1974 sector_div(metadata_dev_size, THIN_METADATA_BLOCK_SIZE >> SECTOR_SHIFT);
1976 return metadata_dev_size;
1980 * When a metadata threshold is crossed a dm event is triggered, and
1981 * userland should respond by growing the metadata device. We could let
1982 * userland set the threshold, like we do with the data threshold, but I'm
1983 * not sure they know enough to do this well.
1985 static dm_block_t calc_metadata_threshold(struct pool_c *pt)
1988 * 4M is ample for all ops with the possible exception of thin
1989 * device deletion which is harmless if it fails (just retry the
1990 * delete after you've grown the device).
1992 dm_block_t quarter = get_metadata_dev_size_in_blocks(pt->metadata_dev->bdev) / 4;
1993 return min((dm_block_t)1024ULL /* 4M */, quarter);
1997 * thin-pool <metadata dev> <data dev>
1998 * <data block size (sectors)>
1999 * <low water mark (blocks)>
2000 * [<#feature args> [<arg>]*]
2002 * Optional feature arguments are:
2003 * skip_block_zeroing: skips the zeroing of newly-provisioned blocks.
2004 * ignore_discard: disable discard
2005 * no_discard_passdown: don't pass discards down to the data device
2007 static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv)
2009 int r, pool_created = 0;
2012 struct pool_features pf;
2013 struct dm_arg_set as;
2014 struct dm_dev *data_dev;
2015 unsigned long block_size;
2016 dm_block_t low_water_blocks;
2017 struct dm_dev *metadata_dev;
2018 fmode_t metadata_mode;
2021 * FIXME Remove validation from scope of lock.
2023 mutex_lock(&dm_thin_pool_table.mutex);
2026 ti->error = "Invalid argument count";
2035 * Set default pool features.
2037 pool_features_init(&pf);
2039 dm_consume_args(&as, 4);
2040 r = parse_pool_features(&as, &pf, ti);
2044 metadata_mode = FMODE_READ | ((pf.mode == PM_READ_ONLY) ? 0 : FMODE_WRITE);
2045 r = dm_get_device(ti, argv[0], metadata_mode, &metadata_dev);
2047 ti->error = "Error opening metadata block device";
2052 * Run for the side-effect of possibly issuing a warning if the
2053 * device is too big.
2055 (void) get_metadata_dev_size(metadata_dev->bdev);
2057 r = dm_get_device(ti, argv[1], FMODE_READ | FMODE_WRITE, &data_dev);
2059 ti->error = "Error getting data device";
2063 if (kstrtoul(argv[2], 10, &block_size) || !block_size ||
2064 block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS ||
2065 block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS ||
2066 block_size & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) {
2067 ti->error = "Invalid block size";
2072 if (kstrtoull(argv[3], 10, (unsigned long long *)&low_water_blocks)) {
2073 ti->error = "Invalid low water mark";
2078 pt = kzalloc(sizeof(*pt), GFP_KERNEL);
2084 pool = __pool_find(dm_table_get_md(ti->table), metadata_dev->bdev,
2085 block_size, pf.mode == PM_READ_ONLY, &ti->error, &pool_created);
2092 * 'pool_created' reflects whether this is the first table load.
2093 * Top level discard support is not allowed to be changed after
2094 * initial load. This would require a pool reload to trigger thin
2097 if (!pool_created && pf.discard_enabled != pool->pf.discard_enabled) {
2098 ti->error = "Discard support cannot be disabled once enabled";
2100 goto out_flags_changed;
2105 pt->metadata_dev = metadata_dev;
2106 pt->data_dev = data_dev;
2107 pt->low_water_blocks = low_water_blocks;
2108 pt->adjusted_pf = pt->requested_pf = pf;
2109 ti->num_flush_bios = 1;
2112 * Only need to enable discards if the pool should pass
2113 * them down to the data device. The thin device's discard
2114 * processing will cause mappings to be removed from the btree.
2116 ti->discard_zeroes_data_unsupported = true;
2117 if (pf.discard_enabled && pf.discard_passdown) {
2118 ti->num_discard_bios = 1;
2121 * Setting 'discards_supported' circumvents the normal
2122 * stacking of discard limits (this keeps the pool and
2123 * thin devices' discard limits consistent).
2125 ti->discards_supported = true;
2129 r = dm_pool_register_metadata_threshold(pt->pool->pmd,
2130 calc_metadata_threshold(pt),
2131 metadata_low_callback,
2136 pt->callbacks.congested_fn = pool_is_congested;
2137 dm_table_add_target_callbacks(ti->table, &pt->callbacks);
2139 mutex_unlock(&dm_thin_pool_table.mutex);
2148 dm_put_device(ti, data_dev);
2150 dm_put_device(ti, metadata_dev);
2152 mutex_unlock(&dm_thin_pool_table.mutex);
2157 static int pool_map(struct dm_target *ti, struct bio *bio)
2160 struct pool_c *pt = ti->private;
2161 struct pool *pool = pt->pool;
2162 unsigned long flags;
2165 * As this is a singleton target, ti->begin is always zero.
2167 spin_lock_irqsave(&pool->lock, flags);
2168 bio->bi_bdev = pt->data_dev->bdev;
2169 r = DM_MAPIO_REMAPPED;
2170 spin_unlock_irqrestore(&pool->lock, flags);
2175 static int maybe_resize_data_dev(struct dm_target *ti, bool *need_commit)
2178 struct pool_c *pt = ti->private;
2179 struct pool *pool = pt->pool;
2180 sector_t data_size = ti->len;
2181 dm_block_t sb_data_size;
2183 *need_commit = false;
2185 (void) sector_div(data_size, pool->sectors_per_block);
2187 r = dm_pool_get_data_dev_size(pool->pmd, &sb_data_size);
2189 DMERR("%s: failed to retrieve data device size",
2190 dm_device_name(pool->pool_md));
2194 if (data_size < sb_data_size) {
2195 DMERR("%s: pool target (%llu blocks) too small: expected %llu",
2196 dm_device_name(pool->pool_md),
2197 (unsigned long long)data_size, sb_data_size);
2200 } else if (data_size > sb_data_size) {
2201 r = dm_pool_resize_data_dev(pool->pmd, data_size);
2203 DMERR("%s: failed to resize data device",
2204 dm_device_name(pool->pool_md));
2205 set_pool_mode(pool, PM_READ_ONLY);
2209 *need_commit = true;
2215 static int maybe_resize_metadata_dev(struct dm_target *ti, bool *need_commit)
2218 struct pool_c *pt = ti->private;
2219 struct pool *pool = pt->pool;
2220 dm_block_t metadata_dev_size, sb_metadata_dev_size;
2222 *need_commit = false;
2224 metadata_dev_size = get_metadata_dev_size_in_blocks(pool->md_dev);
2226 r = dm_pool_get_metadata_dev_size(pool->pmd, &sb_metadata_dev_size);
2228 DMERR("%s: failed to retrieve metadata device size",
2229 dm_device_name(pool->pool_md));
2233 if (metadata_dev_size < sb_metadata_dev_size) {
2234 DMERR("%s: metadata device (%llu blocks) too small: expected %llu",
2235 dm_device_name(pool->pool_md),
2236 metadata_dev_size, sb_metadata_dev_size);
2239 } else if (metadata_dev_size > sb_metadata_dev_size) {
2240 r = dm_pool_resize_metadata_dev(pool->pmd, metadata_dev_size);
2242 DMERR("%s: failed to resize metadata device",
2243 dm_device_name(pool->pool_md));
2247 *need_commit = true;
2254 * Retrieves the number of blocks of the data device from
2255 * the superblock and compares it to the actual device size,
2256 * thus resizing the data device in case it has grown.
2258 * This both copes with opening preallocated data devices in the ctr
2259 * being followed by a resume
2261 * calling the resume method individually after userspace has
2262 * grown the data device in reaction to a table event.
2264 static int pool_preresume(struct dm_target *ti)
2267 bool need_commit1, need_commit2;
2268 struct pool_c *pt = ti->private;
2269 struct pool *pool = pt->pool;
2272 * Take control of the pool object.
2274 r = bind_control_target(pool, ti);
2278 r = maybe_resize_data_dev(ti, &need_commit1);
2282 r = maybe_resize_metadata_dev(ti, &need_commit2);
2286 if (need_commit1 || need_commit2)
2287 (void) commit(pool);
2292 static void pool_resume(struct dm_target *ti)
2294 struct pool_c *pt = ti->private;
2295 struct pool *pool = pt->pool;
2296 unsigned long flags;
2298 spin_lock_irqsave(&pool->lock, flags);
2299 pool->low_water_triggered = 0;
2300 pool->no_free_space = 0;
2301 __requeue_bios(pool);
2302 spin_unlock_irqrestore(&pool->lock, flags);
2304 do_waker(&pool->waker.work);
2307 static void pool_postsuspend(struct dm_target *ti)
2309 struct pool_c *pt = ti->private;
2310 struct pool *pool = pt->pool;
2312 cancel_delayed_work(&pool->waker);
2313 flush_workqueue(pool->wq);
2314 (void) commit(pool);
2317 static int check_arg_count(unsigned argc, unsigned args_required)
2319 if (argc != args_required) {
2320 DMWARN("Message received with %u arguments instead of %u.",
2321 argc, args_required);
2328 static int read_dev_id(char *arg, dm_thin_id *dev_id, int warning)
2330 if (!kstrtoull(arg, 10, (unsigned long long *)dev_id) &&
2331 *dev_id <= MAX_DEV_ID)
2335 DMWARN("Message received with invalid device id: %s", arg);
2340 static int process_create_thin_mesg(unsigned argc, char **argv, struct pool *pool)
2345 r = check_arg_count(argc, 2);
2349 r = read_dev_id(argv[1], &dev_id, 1);
2353 r = dm_pool_create_thin(pool->pmd, dev_id);
2355 DMWARN("Creation of new thinly-provisioned device with id %s failed.",
2363 static int process_create_snap_mesg(unsigned argc, char **argv, struct pool *pool)
2366 dm_thin_id origin_dev_id;
2369 r = check_arg_count(argc, 3);
2373 r = read_dev_id(argv[1], &dev_id, 1);
2377 r = read_dev_id(argv[2], &origin_dev_id, 1);
2381 r = dm_pool_create_snap(pool->pmd, dev_id, origin_dev_id);
2383 DMWARN("Creation of new snapshot %s of device %s failed.",
2391 static int process_delete_mesg(unsigned argc, char **argv, struct pool *pool)
2396 r = check_arg_count(argc, 2);
2400 r = read_dev_id(argv[1], &dev_id, 1);
2404 r = dm_pool_delete_thin_device(pool->pmd, dev_id);
2406 DMWARN("Deletion of thin device %s failed.", argv[1]);
2411 static int process_set_transaction_id_mesg(unsigned argc, char **argv, struct pool *pool)
2413 dm_thin_id old_id, new_id;
2416 r = check_arg_count(argc, 3);
2420 if (kstrtoull(argv[1], 10, (unsigned long long *)&old_id)) {
2421 DMWARN("set_transaction_id message: Unrecognised id %s.", argv[1]);
2425 if (kstrtoull(argv[2], 10, (unsigned long long *)&new_id)) {
2426 DMWARN("set_transaction_id message: Unrecognised new id %s.", argv[2]);
2430 r = dm_pool_set_metadata_transaction_id(pool->pmd, old_id, new_id);
2432 DMWARN("Failed to change transaction id from %s to %s.",
2440 static int process_reserve_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool)
2444 r = check_arg_count(argc, 1);
2448 (void) commit(pool);
2450 r = dm_pool_reserve_metadata_snap(pool->pmd);
2452 DMWARN("reserve_metadata_snap message failed.");
2457 static int process_release_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool)
2461 r = check_arg_count(argc, 1);
2465 r = dm_pool_release_metadata_snap(pool->pmd);
2467 DMWARN("release_metadata_snap message failed.");
2473 * Messages supported:
2474 * create_thin <dev_id>
2475 * create_snap <dev_id> <origin_id>
2477 * trim <dev_id> <new_size_in_sectors>
2478 * set_transaction_id <current_trans_id> <new_trans_id>
2479 * reserve_metadata_snap
2480 * release_metadata_snap
2482 static int pool_message(struct dm_target *ti, unsigned argc, char **argv)
2485 struct pool_c *pt = ti->private;
2486 struct pool *pool = pt->pool;
2488 if (!strcasecmp(argv[0], "create_thin"))
2489 r = process_create_thin_mesg(argc, argv, pool);
2491 else if (!strcasecmp(argv[0], "create_snap"))
2492 r = process_create_snap_mesg(argc, argv, pool);
2494 else if (!strcasecmp(argv[0], "delete"))
2495 r = process_delete_mesg(argc, argv, pool);
2497 else if (!strcasecmp(argv[0], "set_transaction_id"))
2498 r = process_set_transaction_id_mesg(argc, argv, pool);
2500 else if (!strcasecmp(argv[0], "reserve_metadata_snap"))
2501 r = process_reserve_metadata_snap_mesg(argc, argv, pool);
2503 else if (!strcasecmp(argv[0], "release_metadata_snap"))
2504 r = process_release_metadata_snap_mesg(argc, argv, pool);
2507 DMWARN("Unrecognised thin pool target message received: %s", argv[0]);
2510 (void) commit(pool);
2515 static void emit_flags(struct pool_features *pf, char *result,
2516 unsigned sz, unsigned maxlen)
2518 unsigned count = !pf->zero_new_blocks + !pf->discard_enabled +
2519 !pf->discard_passdown + (pf->mode == PM_READ_ONLY);
2520 DMEMIT("%u ", count);
2522 if (!pf->zero_new_blocks)
2523 DMEMIT("skip_block_zeroing ");
2525 if (!pf->discard_enabled)
2526 DMEMIT("ignore_discard ");
2528 if (!pf->discard_passdown)
2529 DMEMIT("no_discard_passdown ");
2531 if (pf->mode == PM_READ_ONLY)
2532 DMEMIT("read_only ");
2537 * <transaction id> <used metadata sectors>/<total metadata sectors>
2538 * <used data sectors>/<total data sectors> <held metadata root>
2540 static void pool_status(struct dm_target *ti, status_type_t type,
2541 unsigned status_flags, char *result, unsigned maxlen)
2545 uint64_t transaction_id;
2546 dm_block_t nr_free_blocks_data;
2547 dm_block_t nr_free_blocks_metadata;
2548 dm_block_t nr_blocks_data;
2549 dm_block_t nr_blocks_metadata;
2550 dm_block_t held_root;
2551 char buf[BDEVNAME_SIZE];
2552 char buf2[BDEVNAME_SIZE];
2553 struct pool_c *pt = ti->private;
2554 struct pool *pool = pt->pool;
2557 case STATUSTYPE_INFO:
2558 if (get_pool_mode(pool) == PM_FAIL) {
2563 /* Commit to ensure statistics aren't out-of-date */
2564 if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti))
2565 (void) commit(pool);
2567 r = dm_pool_get_metadata_transaction_id(pool->pmd, &transaction_id);
2569 DMERR("%s: dm_pool_get_metadata_transaction_id returned %d",
2570 dm_device_name(pool->pool_md), r);
2574 r = dm_pool_get_free_metadata_block_count(pool->pmd, &nr_free_blocks_metadata);
2576 DMERR("%s: dm_pool_get_free_metadata_block_count returned %d",
2577 dm_device_name(pool->pool_md), r);
2581 r = dm_pool_get_metadata_dev_size(pool->pmd, &nr_blocks_metadata);
2583 DMERR("%s: dm_pool_get_metadata_dev_size returned %d",
2584 dm_device_name(pool->pool_md), r);
2588 r = dm_pool_get_free_block_count(pool->pmd, &nr_free_blocks_data);
2590 DMERR("%s: dm_pool_get_free_block_count returned %d",
2591 dm_device_name(pool->pool_md), r);
2595 r = dm_pool_get_data_dev_size(pool->pmd, &nr_blocks_data);
2597 DMERR("%s: dm_pool_get_data_dev_size returned %d",
2598 dm_device_name(pool->pool_md), r);
2602 r = dm_pool_get_metadata_snap(pool->pmd, &held_root);
2604 DMERR("%s: dm_pool_get_metadata_snap returned %d",
2605 dm_device_name(pool->pool_md), r);
2609 DMEMIT("%llu %llu/%llu %llu/%llu ",
2610 (unsigned long long)transaction_id,
2611 (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata),
2612 (unsigned long long)nr_blocks_metadata,
2613 (unsigned long long)(nr_blocks_data - nr_free_blocks_data),
2614 (unsigned long long)nr_blocks_data);
2617 DMEMIT("%llu ", held_root);
2621 if (pool->pf.mode == PM_READ_ONLY)
2626 if (!pool->pf.discard_enabled)
2627 DMEMIT("ignore_discard");
2628 else if (pool->pf.discard_passdown)
2629 DMEMIT("discard_passdown");
2631 DMEMIT("no_discard_passdown");
2635 case STATUSTYPE_TABLE:
2636 DMEMIT("%s %s %lu %llu ",
2637 format_dev_t(buf, pt->metadata_dev->bdev->bd_dev),
2638 format_dev_t(buf2, pt->data_dev->bdev->bd_dev),
2639 (unsigned long)pool->sectors_per_block,
2640 (unsigned long long)pt->low_water_blocks);
2641 emit_flags(&pt->requested_pf, result, sz, maxlen);
2650 static int pool_iterate_devices(struct dm_target *ti,
2651 iterate_devices_callout_fn fn, void *data)
2653 struct pool_c *pt = ti->private;
2655 return fn(ti, pt->data_dev, 0, ti->len, data);
2658 static int pool_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
2659 struct bio_vec *biovec, int max_size)
2661 struct pool_c *pt = ti->private;
2662 struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
2664 if (!q->merge_bvec_fn)
2667 bvm->bi_bdev = pt->data_dev->bdev;
2669 return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
2672 static void set_discard_limits(struct pool_c *pt, struct queue_limits *limits)
2674 struct pool *pool = pt->pool;
2675 struct queue_limits *data_limits;
2677 limits->max_discard_sectors = pool->sectors_per_block;
2680 * discard_granularity is just a hint, and not enforced.
2682 if (pt->adjusted_pf.discard_passdown) {
2683 data_limits = &bdev_get_queue(pt->data_dev->bdev)->limits;
2684 limits->discard_granularity = data_limits->discard_granularity;
2686 limits->discard_granularity = pool->sectors_per_block << SECTOR_SHIFT;
2689 static void pool_io_hints(struct dm_target *ti, struct queue_limits *limits)
2691 struct pool_c *pt = ti->private;
2692 struct pool *pool = pt->pool;
2693 uint64_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT;
2696 * If the system-determined stacked limits are compatible with the
2697 * pool's blocksize (io_opt is a factor) do not override them.
2699 if (io_opt_sectors < pool->sectors_per_block ||
2700 do_div(io_opt_sectors, pool->sectors_per_block)) {
2701 blk_limits_io_min(limits, 0);
2702 blk_limits_io_opt(limits, pool->sectors_per_block << SECTOR_SHIFT);
2706 * pt->adjusted_pf is a staging area for the actual features to use.
2707 * They get transferred to the live pool in bind_control_target()
2708 * called from pool_preresume().
2710 if (!pt->adjusted_pf.discard_enabled) {
2712 * Must explicitly disallow stacking discard limits otherwise the
2713 * block layer will stack them if pool's data device has support.
2714 * QUEUE_FLAG_DISCARD wouldn't be set but there is no way for the
2715 * user to see that, so make sure to set all discard limits to 0.
2717 limits->discard_granularity = 0;
2721 disable_passdown_if_not_supported(pt);
2723 set_discard_limits(pt, limits);
2726 static struct target_type pool_target = {
2727 .name = "thin-pool",
2728 .features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE |
2729 DM_TARGET_IMMUTABLE,
2730 .version = {1, 9, 0},
2731 .module = THIS_MODULE,
2735 .postsuspend = pool_postsuspend,
2736 .preresume = pool_preresume,
2737 .resume = pool_resume,
2738 .message = pool_message,
2739 .status = pool_status,
2740 .merge = pool_merge,
2741 .iterate_devices = pool_iterate_devices,
2742 .io_hints = pool_io_hints,
2745 /*----------------------------------------------------------------
2746 * Thin target methods
2747 *--------------------------------------------------------------*/
2748 static void thin_dtr(struct dm_target *ti)
2750 struct thin_c *tc = ti->private;
2752 mutex_lock(&dm_thin_pool_table.mutex);
2754 __pool_dec(tc->pool);
2755 dm_pool_close_thin_device(tc->td);
2756 dm_put_device(ti, tc->pool_dev);
2758 dm_put_device(ti, tc->origin_dev);
2761 mutex_unlock(&dm_thin_pool_table.mutex);
2765 * Thin target parameters:
2767 * <pool_dev> <dev_id> [origin_dev]
2769 * pool_dev: the path to the pool (eg, /dev/mapper/my_pool)
2770 * dev_id: the internal device identifier
2771 * origin_dev: a device external to the pool that should act as the origin
2773 * If the pool device has discards disabled, they get disabled for the thin
2776 static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv)
2780 struct dm_dev *pool_dev, *origin_dev;
2781 struct mapped_device *pool_md;
2783 mutex_lock(&dm_thin_pool_table.mutex);
2785 if (argc != 2 && argc != 3) {
2786 ti->error = "Invalid argument count";
2791 tc = ti->private = kzalloc(sizeof(*tc), GFP_KERNEL);
2793 ti->error = "Out of memory";
2799 r = dm_get_device(ti, argv[2], FMODE_READ, &origin_dev);
2801 ti->error = "Error opening origin device";
2802 goto bad_origin_dev;
2804 tc->origin_dev = origin_dev;
2807 r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &pool_dev);
2809 ti->error = "Error opening pool device";
2812 tc->pool_dev = pool_dev;
2814 if (read_dev_id(argv[1], (unsigned long long *)&tc->dev_id, 0)) {
2815 ti->error = "Invalid device id";
2820 pool_md = dm_get_md(tc->pool_dev->bdev->bd_dev);
2822 ti->error = "Couldn't get pool mapped device";
2827 tc->pool = __pool_table_lookup(pool_md);
2829 ti->error = "Couldn't find pool object";
2831 goto bad_pool_lookup;
2833 __pool_inc(tc->pool);
2835 if (get_pool_mode(tc->pool) == PM_FAIL) {
2836 ti->error = "Couldn't open thin device, Pool is in fail mode";
2840 r = dm_pool_open_thin_device(tc->pool->pmd, tc->dev_id, &tc->td);
2842 ti->error = "Couldn't open thin internal device";
2846 r = dm_set_target_max_io_len(ti, tc->pool->sectors_per_block);
2850 ti->num_flush_bios = 1;
2851 ti->flush_supported = true;
2852 ti->per_bio_data_size = sizeof(struct dm_thin_endio_hook);
2854 /* In case the pool supports discards, pass them on. */
2855 ti->discard_zeroes_data_unsupported = true;
2856 if (tc->pool->pf.discard_enabled) {
2857 ti->discards_supported = true;
2858 ti->num_discard_bios = 1;
2859 /* Discard bios must be split on a block boundary */
2860 ti->split_discard_bios = true;
2865 mutex_unlock(&dm_thin_pool_table.mutex);
2870 __pool_dec(tc->pool);
2874 dm_put_device(ti, tc->pool_dev);
2877 dm_put_device(ti, tc->origin_dev);
2881 mutex_unlock(&dm_thin_pool_table.mutex);
2886 static int thin_map(struct dm_target *ti, struct bio *bio)
2888 bio->bi_iter.bi_sector = dm_target_offset(ti, bio->bi_iter.bi_sector);
2890 return thin_bio_map(ti, bio);
2893 static int thin_endio(struct dm_target *ti, struct bio *bio, int err)
2895 unsigned long flags;
2896 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
2897 struct list_head work;
2898 struct dm_thin_new_mapping *m, *tmp;
2899 struct pool *pool = h->tc->pool;
2901 if (h->shared_read_entry) {
2902 INIT_LIST_HEAD(&work);
2903 dm_deferred_entry_dec(h->shared_read_entry, &work);
2905 spin_lock_irqsave(&pool->lock, flags);
2906 list_for_each_entry_safe(m, tmp, &work, list) {
2909 __maybe_add_mapping(m);
2911 spin_unlock_irqrestore(&pool->lock, flags);
2914 if (h->all_io_entry) {
2915 INIT_LIST_HEAD(&work);
2916 dm_deferred_entry_dec(h->all_io_entry, &work);
2917 if (!list_empty(&work)) {
2918 spin_lock_irqsave(&pool->lock, flags);
2919 list_for_each_entry_safe(m, tmp, &work, list)
2920 list_add(&m->list, &pool->prepared_discards);
2921 spin_unlock_irqrestore(&pool->lock, flags);
2929 static void thin_postsuspend(struct dm_target *ti)
2931 if (dm_noflush_suspending(ti))
2932 requeue_io((struct thin_c *)ti->private);
2936 * <nr mapped sectors> <highest mapped sector>
2938 static void thin_status(struct dm_target *ti, status_type_t type,
2939 unsigned status_flags, char *result, unsigned maxlen)
2943 dm_block_t mapped, highest;
2944 char buf[BDEVNAME_SIZE];
2945 struct thin_c *tc = ti->private;
2947 if (get_pool_mode(tc->pool) == PM_FAIL) {
2956 case STATUSTYPE_INFO:
2957 r = dm_thin_get_mapped_count(tc->td, &mapped);
2959 DMERR("dm_thin_get_mapped_count returned %d", r);
2963 r = dm_thin_get_highest_mapped_block(tc->td, &highest);
2965 DMERR("dm_thin_get_highest_mapped_block returned %d", r);
2969 DMEMIT("%llu ", mapped * tc->pool->sectors_per_block);
2971 DMEMIT("%llu", ((highest + 1) *
2972 tc->pool->sectors_per_block) - 1);
2977 case STATUSTYPE_TABLE:
2979 format_dev_t(buf, tc->pool_dev->bdev->bd_dev),
2980 (unsigned long) tc->dev_id);
2982 DMEMIT(" %s", format_dev_t(buf, tc->origin_dev->bdev->bd_dev));
2993 static int thin_iterate_devices(struct dm_target *ti,
2994 iterate_devices_callout_fn fn, void *data)
2997 struct thin_c *tc = ti->private;
2998 struct pool *pool = tc->pool;
3001 * We can't call dm_pool_get_data_dev_size() since that blocks. So
3002 * we follow a more convoluted path through to the pool's target.
3005 return 0; /* nothing is bound */
3007 blocks = pool->ti->len;
3008 (void) sector_div(blocks, pool->sectors_per_block);
3010 return fn(ti, tc->pool_dev, 0, pool->sectors_per_block * blocks, data);
3015 static struct target_type thin_target = {
3017 .version = {1, 9, 0},
3018 .module = THIS_MODULE,
3022 .end_io = thin_endio,
3023 .postsuspend = thin_postsuspend,
3024 .status = thin_status,
3025 .iterate_devices = thin_iterate_devices,
3028 /*----------------------------------------------------------------*/
3030 static int __init dm_thin_init(void)
3036 r = dm_register_target(&thin_target);
3040 r = dm_register_target(&pool_target);
3042 goto bad_pool_target;
3046 _new_mapping_cache = KMEM_CACHE(dm_thin_new_mapping, 0);
3047 if (!_new_mapping_cache)
3048 goto bad_new_mapping_cache;
3052 bad_new_mapping_cache:
3053 dm_unregister_target(&pool_target);
3055 dm_unregister_target(&thin_target);
3060 static void dm_thin_exit(void)
3062 dm_unregister_target(&thin_target);
3063 dm_unregister_target(&pool_target);
3065 kmem_cache_destroy(_new_mapping_cache);
3068 module_init(dm_thin_init);
3069 module_exit(dm_thin_exit);
3071 MODULE_DESCRIPTION(DM_NAME " thin provisioning target");
3072 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
3073 MODULE_LICENSE("GPL");